Diagonal Electronic-Structure Hamiltonians via Multi-Basis Decomposition

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Solution Overview

Problem

Simulating electronic structure Hamiltonians is highly complex due to the exponential scaling of required resources as a function of system size, making it challenging to efficiently model and simulate large, complex quantum systems using classical processors.

Innovation Solution

Decompose the electronic structure Hamiltonian into a sum of sub-Hamiltonians, each expressed in a different basis, allowing for efficient simulation using known techniques, and implement Trotter steps with unitary operators on quantum hardware.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the electronic structure Hamiltonian is simulated using a single basis on a quantum computer, then the simulation can be performed with a straightforward quantum circuit, but the computational resources scale exponentially with system size

Engineering Contradiction:
Improveease of simulationVSAvoidcomputational resources
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The electronic structure Hamiltonian is decomposed into a sum of sub-Hamiltonians, each expressed in a different basis. This segmentation allows the simulation to be performed using multiple simpler quantum circuits rather than one complex circuit, reducing the exponential scaling of computational resources with system size while maintaining simulation accuracy.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the Hamiltonian is decomposed into multiple sub-Hamiltonians in different bases, then the computational cost is reduced, but the complexity of the decomposition process increases

Engineering Contradiction:
Improvecomputational resourcesVSAvoidease of decomposition
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The decomposition of the Hamiltonian into sub-Hamiltonians in different bases is performed as a preliminary classical computation step before quantum simulation. This preliminary action prepares the Hamiltonian in a form that reduces quantum computational resources while the classical computer handles the decomposition complexity.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If a compact representation of the Hamiltonian is obtained, then the simulation efficiency is improved, but the precision may be compromised

Engineering Contradiction:
Improvesimulation efficiencyVSAvoidsimulation precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The Hamiltonian is represented in multiple different bases, each providing a different parameterization of the same physical system. By summing sub-Hamiltonians from multiple bases, the method achieves a compact representation that maintains simulation precision while improving efficiency, as each basis captures different aspects of the electronic structure.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3750161B1Techniques for obtaining accurate diagonal electronic structure hamiltonians
Publication Date: 2025.10.29 GOOGLE LLC
  • EP3750161B1 patent drawingFigure 1
  • EP3750161B1 patent drawingFigure 2
  • EP3750161B1 patent drawingFigure 3

AI summary

Methods, systems and apparatus for simulating a physical system described by an electronic structure Hamiltonian expressed in an orthonormal basis. In one aspect, a method includes decomposing the electronic structure Hamiltonian into a sum of sub-Hamiltonians, wherein each sub-Hamiltonian in the sum of sub-Hamiltonians is expressed in one of multiple bases; simulating evolution of the physical system using the decomposed electronic structure Hamiltonian; and using the simulated evolution of the physical system using the decomposed electronic structure Hamiltonian to determine properties of the physical system.